sheet.row + acts as sheet.row +=

[hiphamster]

I'm seeing an odd behavior, which looks like a bug to me.
I create a sheet with a row, then add a new row to that sheet using '+' syntax.

Expected:

Original sheet should not change, as i used '+' and not '+='

Actual:

Original sheet is modified, '+' appears to act as '+='

Here's an example in iPython shell:
`
[nav] In [82]: sheet_a = p.Sheet([['a','b','c']], name='new')

[ins] In [83]: sheet_a.row + ['d','e','f']
Out[83]:
new:
+---+---+---+
| a | b | c |
+---+---+---+
| d | e | f |
+---+---+---+

[ins] In [84]: sheet_a
Out[84]:
new:
+---+---+---+
| a | b | c |
+---+---+---+
| d | e | f |
+---+---+---+

[ins] In [85]: sheet_a.save_as('sheet_a.xls')

[ins] In [86]: sheet_b = p.get_sheet(file_name='sheet_a.xls')

[ins] In [87]: sheet_b
Out[87]:
new:
+---+---+---+
| a | b | c |
+---+---+---+
| d | e | f |
+---+---+---+

[ins] In [88]:

`

[chfw]

pending for v0.6.0 release.